My next two firearm purchases are going to be a Remington 870 and a FAL/G3 of some sort. The bad thing is, I know little to nothing about shotguns. Does anyone have any good resources that I can look at online to learn? I also have some general questions. 1) What is the difference between all the chokes? I want to use both slugs and shot for this shotgun. I was looking at the Express Slug and it had a "fully rifled" choke. Can I use that with regular shells too? 2) Whats different between the sizes of shells. I've seen 2&3/4", 3", 3&1/2" shells. Is it the amount of shot in each, or powder? Also what are the differences in the sizes of shot? I've seen turkey shot, deer shot, 00 shot, 000 shot, ect. 3) Any difference between slugs? The difference between regular and magnum loads are obvious, but are there any other differences that I need to know?